Apparatus to convey material to a pressurized vessel and method for the same

ABSTRACT

The present invention relates to an improved apparatus and method for conveying fibrous, solid and slurry materials, such as granulated wood, rice hulls, chopped cane and the like, to a pressurized vessel, wherein the material being conveyed is compacted in the feeder in a controlled manner to create a seal at the feeder exit into the pressurized vessel whereby the processing pressure in the vessel is maintained. The invention is particularly useful when used in conjunction with a biomass reactor for the production of gas selectively rich in hydrogen and carbon containing components, such as carbon monoxide, carbon dioxide and methane, which in turn, may be converted into a select end product fuel, such as methanol or ethanol or used as a feed gas for an industrial power plant, such a the biomass reactor for producing gas.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority of Provisional Application for Patent,Ser. No. 60/951,198. filed Jul. 21, 2007, which application isincorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Funding from Department of Energy under grant DE-FG36-02GO12025 wasreceived in conjunction with the development of this technology.

REFERENCE TO A “MICROFICHE APPENDIX”

Not applicable

BACKGROUND OF THE INVENTION

The present invention relates to an improved apparatus and method forconveying fibrous, solid and slurry materials, such as granulated wood,rice hulls, chopped cane and the like, to a pressurized vessel. Thematerial being conveyed is compacted in the feeder in a controlledmanner to create a seal at the feeder exit to the pressurized vesselwhich maintains the pressure in the vessel. The invention isparticularly useful when used in conjunction with a biomass reactor forthe production of gas selectively rich in hydrogen and carbon containingcomponents, such as carbon monoxide, carbon dioxide and methane, whichin turn, may be converted into a select end product fuel, such asmethanol or ethanol or used as a feed gas for an industrial power plant,such as the biomass reactor for producing gas described in U.S. Pat. No.6,767,375 owned by the inventor of the present invention.

Gasification of biomass material such as wood, woodchips, sawdust, woodcharcoal, rice, sugar cane hulls and other particulate cellulosicmaterials has become of increasing interest and importance because ofthe volatility of petroleum prices, dwindling of fossil fuels, such asdomestic petroleum and natural gas resources and the increaseddependence of the United States on international imports of these fuels.Gasification of coal and biomass has been practiced for over one hundredyears and there are many varieties and types of gasifiers and methods ofgasification. One method of gasification applicable to biomass materialis pyrolysis. Pyrolysis is the breakdown of the biomass by heat atelevated temperatures (e.g., about 400 to about 1200 degrees Fahrenheit)to yield an intermediate gas which is ultimately transformed into amarket fuel (gas or liquid such as methane or ethanol). Inclusion of atransport gas, such as oxygen or steam, during the pyrolysis, assists inthe production of an intermediate gas containing carbon monoxide, carbondioxide and hydrogen, useful in later conversion into fuel such asethanol, methanol, ammonia or methane. Similarly, other gas additions,such as air or nitrogen, may be used for synthesis gas having othermakeup required for different end products.

As mentioned, the present invention is particularly useful when used inconjunction with the biomass reactor for producing gas as described inU.S. Pat. No. 6,767,375 (“'375 patent”) owned by the inventor of thepresent invention. The '375 patent provides an improved method andapparatus for producing a synthesis gas from a biomass feed material. Inone aspect, the '375 patent incorporates a reactor vessel heated, atleast in part, by a heat source such as an electric or natural gasheating unit. The reactor vessel generally includes a helical coil orconduit of many turns utilized for carrying the biomass feed materialand an appropriate transport gas, throughout which the pyrolytic processis performed. Some embodiments of the helical coil may have a coolingsystem associated with at least a portion of a support systeminterconnecting the helical coil with the reactor vessel.

The many turns of this helical coil may be disposed in the vessel in anumber of appropriate locations, but are preferably disposed adjacent asidewall of the reactor vessel. This preferred arrangement of the coilrelative to the reactor vessel may be said to provide an air gap betweenthe coil and the vessel sufficient to produce convective heating. Thecoil generally receives a feed of the biomass material, preferably inground or granulated form, which is mixed and transported through thereactor coil utilizing the transport gas. In some embodiments, thetransport gas may provide heat and/or chemical support to the pyrolysisprocess in addition to the externally supplied heat that is utilized totransform the biomass material into a target synthesis gas in thereactor coil. The rate of and control over the pyrolysis process in thereactor coil are preferably effected by the inclusion of separatedradiant and convective heat zones in the reactor vessel. These heatzones, at least in one embodiment, may generally be determined by thelocation of a heat shield disposed in the vessel. This heat shield mayexhibit any of a number of appropriate designs. For instance, in onepreferred embodiment, the heat shield includes an at least generallycylindrical section. Moreover, this heat shield may be disposed in anyeffective location relative to the coil. It is, however, preferred thatthe heat shield be located at least generally, concentrically of thecoil. Further, it is also generally preferred that this heat shield belocated in an upper region of the vessel above the heat source. The heatshield preferably includes a truncated conical section disposed toward abottom of the heat shield (closed at an end nearest the heat source) tobetter establish transition between the radiant and convective heatzones and to facilitate convective heating in the respective zone.

Preferably, the reactor vessel includes a pressurized mixing vessel inwhich the biomass feed material is collected, mixed and supplied to thereactor coil. This pressurized vessel may include a number ofappropriate mechanisms capable of maintaining a seal against a loss ofoperating pressure within the mixing chamber while promoting the biomassfeed material and/or the transport gas to pass therethrough.

It is desirable to mix the transport gas and biomass feed together in apressurized vessel before they enter the reactor. A transport gasutilized to mix and transport the biomass feed and carry it to thereactor is input into the pressurized vessel. The biomass feed materialsare generally added to the pressurized vessel at atmospheric pressure,or at some lower pressure than that of the mixer; thus, there would bebackflow of the transport gas through the feeding mechanism and into thevessel containing the feed material unless there is an adequate sealbetween the vessels.

In the '375 patent, the material is introduced into the pressurizedvessel from a hopper through a veined rotary valve. The hopper containsbulk raw material which is supplied to the rotary valve by means of aconventional metering rotary valve feeding the amount of biomass feedmaterial to the pressurized vessel preferably in a manner and/or at arate sufficient for a particular gas output. In order to ensure that nosignificant amount of build up of biomass feed material occurs in thehopper at the rotary valve, the rotary valve is preferably operated at ahigher RPM than the metering valve.

As noted, one function of the rotary valve is to at least generally sealthe interior of the pressurized vessel to the atmosphere. This generallyhelps maintain gas pressure within the system as well as promote thepressurized feed of mixed biomass and transport gas traveling from thepressurized vessel to the reactor. The biomass feed is introduced intothe pressurized vessel by means of a rotary valve which may be rotatedutilizing any appropriate means, such as an electric motor. The rotaryvalve may be said to facilitate the supply of material in being movedinto the lower portion of the drop tube and toward the bottom of thepressurized vessel. Incidentally, the metering valve and the rotaryvalve are interconnected by an upper portion as the drop tube. The droptube may be said to contain the biomass feed as a transit to and fromthe rotary valve. What may be characterized as a mating of veins withside walls of the rotary valve is such that a seal against back pressureis at least generally provided thereby between the lower and upperportions respectively of the drop tube. This seal of sorts may be saidto assist in maintaining the pressure of the incoming transport gas toprevent over heating of the rotary valve.

Due to the nature of the feed materials, they may lump together and flownon-uniformly into the mixer. This non-uniform flow can clog the feedingmechanism and create problems maintaining pressure in the mixer. The'375 patent system utilizes a rotary vane valve as a feeder which hasseveral issues. One issue with that design is pocket plugging. The feedmaterial initially falls into the pockets of the valve. This material iscompressed as the pressure from the system enters the pockets. Moisturein the material or from the system transport gas causes the material tostick in the pocket. The material does not exit the pocket at thedischarge position, but is carried around to the feed inlet positionwhere less material can enter the pocket. This continues until thepocket is full of material and the feed system is completely plugged.

Temperature variations also cause problems for the rotary valve feeder.The heat from the transport gas is transferred to the rotary valvefeeder which causes expansion and contraction. The lower portions of therotary valve are exposed to greater heat than the lower portions;therefore, the expansion is not uniform throughout the valve. The sealcreated by the rotary valve is dependent on a very close tolerancebetween the rotating vanes and the rotary valve body. Temperaturevariations in the rotary valve components change these tolerances andcause either loss of pressure and leakage (if the tolerance isincreased) or damage to the valve and seizing of the valve (if thetolerance decreases).

When using the rotary valve feeder, after the material is added to thepocket that pocket is pressurized before the material is deposited inthe pressurized vessel. If this step is skipped, the pressure in thepressurized vessel may prevent the material from exiting the pocket atthe valve outlet. Another issue, is that if the pressurized vesselcontains moist gas, that gas seeps into the pocket adding moisture tothe feed material and possibly causing clumping to occur. A inert gassuch as nitrogen is typically used to pressurize the pocket. Nitrogendilutes the transport gas and requires larger system components tohandle the required amount of transport gas plus the additional inertgas. The present invention eliminates the need to pressurize the feeder.

After discharging the material, the rotary valve pockets fill withpressurized transport gas. The pressurized transport gas must beevacuated before the valve pocket returns to the feed inlet position. Ifnot, the transport gas will discharge into the feed inlet area and asmaller amount of feed material or none at all will be able to enter therotary valve pocket. The discharge of transport gas containing moistureat the feed inlet introduces moisture into the feed material and maycause plugging at the feed inlet.

The present invention is an improvement over the '375 patent feed systemand allows for conveying fibrous solid and slurry materials, such asbiomass materials, in a uniform matter. It utilizes the material itselfto maintain the seal, thus allowing a vessel, such as a mixer, tomaintain its pressure while material is being added to it. The presentinvention solves the challenges listed above by blocking flow of thetransport gas from the pressurized vessel into the feeder with thematerial plug. In the present invention, the material is only exposed tothe transport gas beyond the conveying means at the point where it isdischarged, so there is no potential for moist feed material to plug theconveying means. Likewise, a close tolerance between rotating andstationary parts is not critical to maintain a seal. Additionally, themoving parts do not rotate past stationary parts which are at differenttemperatures as with the rotary valve. Thus, the challenges presented bythe temperature variations and the rotary valve are eliminated. Theconveying mechanism of the present invention does not contact thetransport gas thus the exhaust cycle for removing trapped transport gasfrom the empty rotary valve pocket is eliminated.

There are numerous commercial examples of auger systems such as thosewhich feed plastic pellets into injection molding machines. In thosesystems, the plastic pellets melt and flow uniformly into the augerwhich transports the plastic into the injection molding machine. Thepresent invention differs from those systems because it is able tohandle many different compositions of fibrous solid and slurry materialswhich otherwise tend to flow non-uniformly and provides a uniform flowof material into a pressurized vessel.

BRIEF SUMMARY OF THE INVENTION

The present invention provides an improved apparatus and method forconveying fibrous solid and slurry materials into a pressurized vesselwhile maintaining the pressure in that vessel by utilizing the materialto create a seal.

One use of the present invention is to feed material into a flowing gasstream at a pressure. Another use of the present invention is to feedmaterial into a vessel, grinder, processing machine or the like which isat a pressure.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of the conveying apparatus including a crosssection of the discharge housing.

FIG. 2 is a side view of the conveying apparatus including a crosssection of the discharge housing with a cut away showing the auger.

FIG. 3 is a side, cross sectional view of the discharge housing showingthe conical end being forced out of the material retention chamber.

FIG. 4 is a side, cross sectional view of the discharge housing showingthe material retention chamber open and material exiting the materialretention chamber.

FIG. 5 is a side, cross sectional view of the discharge housing showingthe material retention chamber closed off by the conical end.

FIG. 6 is a perspective view of the conveying apparatus as attached tothe pressurized vessel.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, the present invention includes an auger 4 enclosedin a pipe 1 with an inlet 5 and an outlet 10 for transporting biomassmaterial. (FIG. 2 shows the auger 4) The auger 4 is powered by a drivemotor 6 (See FIG. 6). The pipe 1 and auger 4 are made of any durablematerial such as carbon steel or stainless steel. The abrasiveness andhardness of the material should be considered by those skilled in theart when determining the particular materials of construction of thepipe 1 and auger 4. Because the auger 4 is forcing the biomass materialagainst the interior walls of the pipe 1, those more highly abrasivematerials may cause considerable frictional wear on the interior wallsof pipe 1 and auger 4. Those skilled in the art should recognize thehigher the speed of auger 4, the greater the likely wear on the pipe 1and auger 4. In embodiments where the material is highly abrasive, thespeed of auger 4 (and thus the material feed speed) should be relativelyminimized to reduce wear to a tolerable level. In one embodiment, thematerial is a fibrous, biomass feed, such as saw dust—a byproduct ofprocessing lumber for use in furniture production or as buildingmaterial at commercial sawmills, but the material could be any solid orslurry biomass material.

The inlet 5 is connected to a metering device (not shown) which controlsthe feed rate of the material to be conveyed by the auger 4 to thepressurized vessel 2. The metering device can be any commerciallyavailable metering device such as a metering screw, belt feeder, rotaryvalve or the like, such as the Fuller-Kovako rotary feeder illustratedin U.S. Pat. No. 6,767,375). The rate of material transfer is notcontrolled by the auger 4 speed, but by the speed of the meteringdevice; therefore, to avoid accumulation of feed material at the inlet5, the auger 4 should be operated at a speed capable of handling morematerial than is being conveyed by the metering device. The ratio ofmetering device outlet speed to auger 4 speed is dependent on manyparameters such as size, type of material, and type of metering device.For example, in one embodiment, the auger runs between 10% to 33% fasterthan the metering device.

The outlet 10 is adjacent to a discharge housing 15 at a first sideopening 16 in the discharge housing 15. The discharge housing 15 alsohas a second side opening 17 and a bottom opening 18. A materialretention chamber 20 is disposed between the outlet 10 of the pipe 1 andthe first side opening 16 of the discharge housing 15. The materialretention chamber 20 extends into the discharge housing 15. In oneembodiment the material retention chamber 20 is created by a portion ofthe pipe 1 which extends beyond the auger 4. In another embodiment, thematerial retention chamber 20 is a separate section of pipe attached tothe outlet 10 of pipe 1. The material retention chamber 20 has a chamberinlet 21 and a chamber outlet 22.

A piston 25 is connected to the discharge housing 15 at the second sideopening 17. The piston 25 is comprised of a cylinder 26 and a plunger 27which is enclosed in the cylinder 26. The plunger 27 moves horizontallywithin the cylinder 26 when pressure is applied to either end of thecylinder 26. The plunger has a conical end 28 which extends into thedischarge housing 15 and a rear end 29 which is enclosed in the cylinder26. The conical end 28 may be made of plastic or metal and has a smoothsurface, however having a surface sufficiently suitable wear resistantto withstand the frictional flow of the compressed biomass material. Inone embodiment, pressure is applied to the rear end 29 of the cylinder26 by an air or hydraulic pressure system through pressure fitting 32.The pressure setting is controlled as part of the overall control of theconveying system. The air or hydraulic pressure setting can becontrolled or correlated to the power input of the auger 4, for instanceby monitoring the drive motor 6. In another embodiment, the pressurecontrol can be set to adjust the air or hydraulic load to keep thepressure higher.

Referring now to FIG. 2, the pressure on the cylinder is set so that theplunger 27 extends out of the cylinder 26 and into the discharge housing15 far enough that the conical end 28 is inserted into the chamberoutlet 22 of the material retention chamber 20 closing the materialretention chamber 20 off from the discharge housing 15. The amount ofpressure set on the rear end 29 of the plunger 27 and the horsepowerdelivered by the auger 4 varies according to the characteristics of thematerial, such as particle size, moisture, compressibility, friability,and elasticity to name a few. For example, finer, dry materials requiremore pressure to compress to a consistency where the gas will notpermeate through void spaces in the mixture and the auger 4 must delivermore horsepower. Coarse, wet materials require less pressure to compressbecause the moisture fills void spaces more readily and prevents any gasfrom permeating through the plug and the auger 4 can deliver lesshorsepower. The total horsepower delivered by the auger must overcomeboth the wall friction and the cone pressure. The cone pressure adds tothe wall friction to give the required total compaction power.

As material is transferred through the pipe 1 by the auger 4, itcollects in the material retention chamber 20 until material retentionchamber 20 is filled. Referring now to FIG. 2, as the material fills thematerial retention chamber 20, the solid particles are compressedtogether creating a material plug as at 23 in the material retentionchamber 20. The build up of material in material retention chamber 20exerts pressure on the conical end 28. When enough material has built upin the material retention chamber 20 that the pressure on the conicalend 28 exceeds the pressure setting on the rear end 29, the materialforces the plunger 27 to move horizontally in the cylinder 26, openingthe chamber outlet 22 so that material exits the material retentionchamber 20 into the discharge housing 15 as shown in FIGS. 3 and 4. Thedrive motor 6 on the auger 4 should be sized to successfully drive theauger 4 against the pressure created by piston 25 and force the materialto compact creating material plug 23.

The material plug 23 thus creates a seal between the pipe 1 and thedischarge housing 15 preventing the backflow of gas from the pressurizedvessel 2 into the pipe 1 when the conical end 28 is not itself insertedinto the material retention chamber 20. Although some material isdischarged, the auger 4 feeds enough new material into the materialretention chamber 20 to maintain the material plug 23. The pressure onrear end 29 forces the plunger 27 to move horizontally in the cylinder26, extending the plunger 27 far enough into the discharge housing 15that it is reinserted into the chamber outlet 22. (See FIG. 5)

The pressure setting on the rear end 29 of the plunger 27 and the speedof the auger 4 are parameters that are controlled to maintain thematerial plug 23 and the seal it creates. These two parameters determinethe degree of compaction of the material and the force exerted by thematerial on the walls of the pipe 1. The speed of the auger 4 should beset such that the material discharge rate exceeds the rate of permeationof the pressurized gas from pressurized vessel 2 through the plug 23. Inone embodiment the auger 4 runs at a constant speed to ensure noaccumulation of material at the inlet 5 and a constant rate of dischargeof material at chamber outlet 22. In another embodiment, the auger 4speed varies, but is dependent on the metering device speed and ismaintained at a speed slightly greater than the metering device speed.This would be particularly useful in situations where the operatingparameters of the pressurized vessel fluctuate. In yet anotherembodiment, the auger 4 speed will be set to never drop below a minimumspeed in order to maintain the plug 23 and seal and prevent the loss ofsystem pressure. This would also be particularly useful in situationswhere the operating parameters of the pressurized vessel fluctuate.

The amount of pressure on the rear end 29 of the plunger 27 is dependenton the characteristics of the feed material and the pressure of thepressurized vessel 2. In one embodiment, the pressure on the rear end 29is varied by adjusting the horsepower delivered by the auger or thespeed of the auger. In another embodiment, the pressure on the rear end29 is 30 psig greater than the maximum system pressure in thepressurized vessel 2.

The size of the material retention chamber 20 and the distance from thechamber outlet 22 and the conical end 28 of the plunger 27 variesaccording to the type, grain size, moisture content, and othercharacteristics of the material. The angle of vertex of a cone is theangle between the axis of the cone and the sloped side of the cone. Thelarger the diameter of the material retention chamber 20, the greaterthe degree of the angle of the vertex of the cone of the conical end 28.In embodiments where the material is fine and free flowing, the diameterof the base of conical end 28 should be equal to or greater than thediameter of chamber outlet 22 so that the conical end 28 creates a seal.In other embodiments where the material is drier and resists free flow,the diameter of the base of conical end 28 is less than the diameter ofchamber outlet 22.

The pressure, speed of auger controlled to maintain seal 23 is verydependent on the type of material biomass material which is being fed.In the illustrated examples for sawdust, the pressure applied to theplunger should produce a force on the sawdust plug in the range of 15 to25 psi. This is applicable to examples 1 and 2, below and assumes anauger speed which is 10 to 50% greater than the metering flow. Changesin the compaction nature of the material, as for materials other thanthe sawdust preferably used, will cause this requirement to change. Asstated above, finer materials (including sawdust) will require highercompaction to ensure that the reactor gases do not permeate backwardsthrough the sealing plug 23. This requires plug forces which producemore than the 15 to 40 psi which are used for the materials of theexamples. Also, as the reactor pressure increases, a higher force shouldbe used. As may be observed, the force, 15 to 40 psi, is in the range ofthe pressures sealed against in the illustrative examples. At the start,as the reactor pressure is increased, the plunger force applied to thesawdust should equal the reactor pressure.

Angle of the vertex of cone as compared to the size of chamber variesdepending on material type and it is important to ensure that adequateforce is applied to the sawdust (and any processed biomass material) todeliver the required compaction to seal against pressure leakage at theplug 23. The cone also serves to break up the plug (i.e., change thedirection of the biomass material flow) so that it can enter the steamentrainment area. As the size of the chamber increases (relative to thesize of the particles) the cone angle must also increase. It isappropriate angles for materials other than the sawdust of the examplesdisclosed must be optimized to maintain the flow and plug however it isexpected that that the angles will be between 45 and 80 degrees. Forvery large chamber diameters, it is anticipated that cone angles ofslightly less than 90 degrees will be appropriate, albeit appearing asalmost be a flat plate. The ultimate cone angle limit is 90 degrees.

Other features of the invention will become apparent in the course ofthe following examples which are given for illustrations of theinvention and are not intended to be limiting thereof.

EXAMPLE 1

The following is an example of the apparatus of the present invention.The material retention chamber 20 has a three inch diameter, the angleof the vertex of the cone of the conical end 28 is approximately 45degrees, the utilized motor horsepower is 10 hp, the maximum speed ofthe auger is 50 rpm, and the auger diameter is 3 inches. The sawdustwood rate of feed is about 100 pounds per hour and the reactor pressureis 10 psig, the sawdust has an average moisture of about 10% and graintop size of about ⅛ inch.

EXAMPLE 2

The following is an example of a second embodiment of apparatus of thepresent invention. The material is sawdust and the material retentionchamber 20 has an eight inch diameter, the angle of the vertex of thecone of the conical end 28 is between 70 and 80 degrees. The auger speedis 25 rpm, producing a feed rate of about 800 pounds of sawdust per hourwith a reactor pressure of about 40 psig. The useful horsepower of themotor is 15 hp. The auger size is 8 inches in diameter. When thepressurized vessel 2 is run at 30 psig, the pressure on the rear end 29is 60 psig. It is noted that the 50% increase of horsepower utilized inexample 2 represents the ratio of frictional area over the volume forthe diameter (3 vs. 8 inches) of the feeders. It is observed that formaterials other than sawdust (at the given % of moisture) a startingpoint is proposed in the application of the data above as adjusted forthe coefficient of friction between the “new” material and the materialof construction used for the retention chamber. If the “new” coefficientis higher than the coefficient for the sawdust, more horsepower for thedrive motor will be required. The increase will be roughly the ratio ofcoefficients of friction.

It is preferred that the ratio of the metering device flow to augerspeed be an auger speed which will deliver 10% more flow than themetering device. Running at less of a ratio usually induces problemswith buildup in the auger inlet. It is preferable to generally operateat an auger speed which will deliver 25 to 50% more flow than themetering device. It is noted that running at auger speeds of 200 to 300%of the metering device can be maintained, there is little useful effect.It is observed that to avoid excessive wear in the feeder stream, the 25to 50% range appears to be appropriate for most applications.

The material exits the discharge housing 15 through the bottom opening18 which is attached to a pressurized vessel 2 at a feed inlet 31. (SeeFIG. 2) In some embodiments, a grinder 32 may be attached to the bottomopening 18 to break up the material as it enters the pressurized vessel2 through the feed inlet 31 (See FIG. 2). A grinder 32 may be includeddepending on the material and its moisture content. For material that isnominally dry and friable enough to break up on its own, like sawdust, agrinder 32 is not required. However, a grinder 32 is useful formaterials which have a higher moisture content and exhibit a paste-likeconsistency when compacted, like chicken litter. The grinder 32 may beany device which helps break up clumped material and maintain a uniformflow into the pressurized vessel 2. Some examples of acceptableconfigurations of grinders 32 are a rotating drum against rotating drumor breaker plate, but any commercially available grinder that iscontained within the system piping and does not allow accumulation ofmaterial above the grinder 32 is acceptable.

Upon start up, material is fed through the auger 4 until material plug23 is formed. When the pressure exerted by the material plug 23 on theconical end 28 exceeds the pressure on rear end 29, the feed valve 33connecting the feeder to the feed inlet 31 of the pressurized vessel 2is opened to start the material feed. (See FIG. 6)

Although the present invention has been described in terms of specificembodiments, it is anticipated that alterations and modificationsthereof will no doubt become apparent to those skilled in the art. It istherefore intended that the following claims be interpreted as coveringall alterations and modifications that fall within the true spirit andscope of the invention.

1. A conveying apparatus for adding fibrous solids or slurries to apressurized vessel comprising: a feed hopper containing a fibrousmaterial for addition to a pressurized vessel; a pipe having an inletand an outlet, said inlet connected to said feed hopper; an auger fortransporting said material from said inlet to said outlet enclosed insaid pipe, said auger extending from said inlet to said outlet; adischarge housing intermediate to said pipe outlet and said pressurizedvessel, said discharge housing having a first opening, a second opening,and a third opening; a material retention chamber for collecting anddischarging said fibrous material having a chamber inlet and a chamberoutlet, said chamber inlet connected to said pipe outlet and projectingthrough said first opening into said discharge housing such that saidmaterial is discharged to said discharge housing when said chamberoutlet is not sealed; a piston having a conical end for sealing saidmaterial retention chamber outlet, said piston disposed for horizontalmovement with respect to said discharge housing and positioned acrossfrom said material retention chamber outlet, said conical end engagingsaid chamber outlet thereby creating a seal when said conical end isengaged and preventing the discharge of said material into saiddischarge housing; and said pressurized vessel having a feed inletadjacent to said third opening of said discharge housing whereby saidmaterial is transferred from said discharge housing to said pressurizedvessel.
 2. The conveying apparatus of claim 1 further comprising: ametering device intermediate to said feed hopper and said pipe inlet forregulating flow of said fibrous material.
 3. The conveying apparatus ofclaim 1 further comprising: a grinder intermediate to said third openingin said discharge housing and said feed inlet of said pressurized vesselfor maintaining uniform flow into said pressurized vessel.
 4. Theconveying apparatus of claim 1 further comprising: a feed valveintermediate to said third opening in said discharge housing and saidfeed inlet of said pressurized vessel for controlling flow into saidpressurized feeder.
 5. The conveying apparatus of claim 1 wherein: saidconical end of said piston has a angle of vertex of about 45 degrees;and said material retention chamber and chamber outlet have a diameterof about three inches.
 6. The conveying apparatus of claim 1 wherein:said conical end of said piston has a angle of vertex ranging between 45and 80 degrees; and said material retention chamber and chamber outlethave a diameter ranging between three and eight inches.
 7. The conveyingapparatus of claim 1 further comprising: a reactor for processing saidmaterial connected to said pressurized vessel.
 8. A conveying apparatusfor adding biomass feed to a pressurized vessel comprising: a feedhopper containing a biomass material for addition to a pressurizedvessel; a pipe having an inlet and an outlet, said inlet connected tosaid feed hopper; an auger for transporting said material from saidinlet to said outlet enclosed in said pipe, said auger extending fromsaid inlet to said outlet; a discharge housing intermediate to said pipeoutlet and said pressurized vessel, said discharge housing having afirst opening, a second opening, and a third opening; a materialretention chamber for collecting and discharging said fibrous materialhaving a chamber inlet and a chamber outlet, said chamber inletconnected to said pipe outlet and projecting through said first openinginto said discharge housing such that said material is discharged tosaid discharge housing when said chamber outlet is not sealed; a pistonhaving a conical end for sealing said material retention chamber outlet,said piston disposed for horizontal movement with respect to saiddischarge housing and positioned across from said material retentionchamber outlet, said conical end engaging said chamber outlet therebycreating a seal when said conical end is engaged and preventing thedischarge of said material into said discharge housing; and saidpressurized vessel having a feed inlet adjacent to said third opening ofsaid discharge housing whereby said material is transferred from saiddischarge housing to said pressurized vessel.
 9. The conveying apparatusof claim 8 further comprising: a metering device intermediate to saidfeed hopper and said pipe inlet for regulating flow of said biomassmaterial.
 10. The conveying apparatus of claim 8 further comprising: agrinder intermediate to said third opening in said discharge housing andsaid feed inlet of said pressurized vessel for maintaining uniform flowinto said pressurized vessel.
 11. The conveying apparatus of claim 8further comprising: a feed valve intermediate to said third opening insaid discharge housing and said feed inlet of said pressurized vesselfor controlling flow into said pressurized feeder.
 12. The conveyingapparatus of claim 8 further comprising: a biomass reactor forgasification of said biomass material connected to said pressurizedvessel.
 13. The conveying apparatus of claim 8 wherein: a biomassreactor for production of synthesis gas by pyrolysis of said biomassmaterial connected to said pressurized vessel.
 14. A method oftransferring fibrous solids or slurries to a pressurized vesselutilizing said fibrous material to maintain a seal to prevent backflowof gas from said pressurized vessel which comprises: engaging a conicalend of a piston with a material retention chamber intermediate to a feedhopper and a pressurized vessel by applying an external pressure to arear end of said piston thereby blocking an outlet of said materialretention chamber; conveying a fibrous material from a feed hopper tosaid material retention chamber causing said material to accumulate insaid material retention chamber forming a material plug which creates aseal between said feed hopper and said pressurized vessel to preventbackflow of gas from said pressurized vessel, said material plug appliesan internal pressure on said conical end of said piston; and forcingsaid conical end of said piston to disengage with said materialretention chamber when said internal pressure exceeds said externalpressure thereby discharging said material from said material retentionchamber to said pressurized vessel but retaining said material plug insaid material retention chamber to prevent backflow of gas from saidpressurized vessel.
 15. The method of claim 14 further comprising:metering said material into said material retention chamber at acontrolled rate.
 16. The method of claim 14 further comprising: grindingsaid material that is discharged from said material retention chamberbefore it enters said pressurized vessel.
 17. The method of claim 14further comprising: controlling flow of material into said pressurizedvessel utilizing a valve intermediate to said material retention chamberoutlet and said pressurized vessel.
 18. The method of claim 14 wherein:a vessel pressure of about 30 psig is maintained in said pressurizedvessel; and said external pressure applied to said rear end of saidpiston is about 60 psig.
 19. The method of claim 14 wherein: saidfibrous material is a biomass material.
 20. The method of claim 19further comprising: mixing said biomass material with a transport gas insaid pressurized vessel; and transferring said biomass material andtransport gas mixture to a biomass reactor for production of a synthesisgas by pyrolysis.